title: A cloned unique gene of Drosophila melanogaster contains a repetitive 3' exon whose sequence is present at the 3' ends of many different mRNAs.
abstract: We have started a cloned genomic DNA fragment approximately 7 kb long (denoted as H55) from the 7B3-4 region in the X chromosome of Drosophila melanogaster. The major part of the fragment is a single-copy sequence. It directs the synthesis of mRNA that makes up approximately 0.1% of the cytoplasmic poly(A)+ RNA from Drosophila embryos. The H55 gene is split by an intervening sequence, yielding a large single-copy exon and a small repetitive 3' exon represented by hundreds of copies in the genome. This repetitive sequence ("suffix") is also present at the 3' ends of approximately 2% of all cytoplasmic poly(A) chains.
mesh_terms: D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular / Q000379:methods; D004331:Drosophila melanogaster / Q000235:genetics*; D005796:Genes; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D011061:Poly A / Q000235:genetics; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D011061:Poly A